Automatic ribbon-reversing mechanism for cash registers



-May 10, 1927. 1,628,164

W. E. LIPPERT AUTOMATIC RIBBON REVERSING MECHANISM FOR CASH REGISTERS Filed Jan. 51. 1924 3 Sheets-Sheet 1 MiLTERE L/PPE/WI k WM May 10 1927. 1,628,164

w. E. LIPPERT AU TOMATIC RIBBON REVERSING MECHANISM FOR CASH REGISTERS Filed Jan. 51. 1924' s Sheets-Sheet 2 I 1,628,164- M y w. E. LIPPERT AUTOMATIC RIBBON REVERSING MECHANISM.FOR CASH REGITERS Filed Jan. 5L 1924 3 Sheets-Sheet 3 /e/ 62 '3 5 2 a; a

Patented May 10, 1927.

UNITED STATES 1,628,164 PATENT OFFICE...

WALTER E. LIRiPERT, OF ILION, NEW YORK, ASSIGNOR TO REMINGTON ARMS COM- PANY, INC., A CORPORATION OF DELAWARE.

AUTOMATIC RIBBON-REVERSING MECHANISM FOR CASH REGISTERS.

This invention relates primarily to accounting machines, and more particularly to means provided for causing the automatic reversal of an inking ribbon employed in such machines for purposes of printing on a record medium.

It is a common expedient in all forms of recording machines to employ an inking ribbon adapted to be passed from one retaining spool to another and in so doing to cause it to pass between a series of type and a record medium so as to provide means for producing a printed entry on the medium, when a platen (or the type) ismoved to take an impression. Since such inking ribbons are capable of causing many records to be taken from each section it is also common to provide means whereby the ribbon may be fed back and forth across the print ing line many times before the ribbon is discarded and such shifting means have commonly been made to reverse their action automatically so that without the attention of the operator the ribbon is shifted from one spool to the other and back again continuously.

It is an object of this invention to provide simple and eflicient means for rotating the ribbon spools in either direction and at the same time to positively prevent rotation of the spools in a direction contrary to that for which the mechanism is set.

111 accomplishing the above object it has been found desirable to centralize the control as to the direction in which the ribbon is to be fed by causing it to act directly on only one of the spools, the other spool being always rotated to correspond with the movement of the controllingspool. Another object of this invention has, therefore, been to improve and render more effective the means for causing reverse rotations of a single spool at different times during the operation of the machine.

A further object has been to produce a reversing mechanism of the character indicated above which is caused to reverse its action by the effect of excess tension resulting from the complete unwinding of the ribbon from one of the spools.

A more specific object of the invention is to provide an inter-control between the driving means for the controlling ribbon spools and the detent devices employed for preventingundesirable rotation of the spool Application filed January 31, 1924. Serial No. 689,760.

in the direction opposite to that in which it is infie tledyw he driven. "The result of this provislon is that detent devices which are particularly positive in their action may be employed to prevent rotation of a spool in either direction alternatively.

Other objects and advantages of the i11- vention will be apparent 'from'the detailed description which follows-c onsidered in connection ,Fvith .the accompanying. drawings which form apart of the disclosure.

The inventio'n-isishown herein in its preferred embodiment; as applied to a cash register of the type disclosed in the copending application of Frederick L. Fuller, 263,125, filed Nov.* 19, 1918,', although obviously it may be applied with only slight variatlons to numerous other types of recording machines. Only so m'uc'hof the general features of the cash register as are required for a full understanding of the ribbon reversing mechanism are shown in the drawings, in which I Y Fig. 1 discloses a section in elevation through a cash register of suitable type showing the general operating features of the machine.

Fig. 2 shows a left side view in elevation of the printer frame of such cash register.

Fig. 3 shows the same printer frame, in elevation, as viewed from the right.

Fig. 4 is a detail showing the supporting and feeding means for the inking ribbon at opposite sides of the machine.

Figs. 5, 5 5 5 and 5 are detail views of the driving and detent means for the left hand spool of the inking ribbon, showing the parts in various different positions assumed during operations of the machine.

Fig. Gis a view similar to Fig. 5 with certainbf the driving elements removed to more clearly exhibit the detent controlling means.

The machine disclosed in the drawings is of the key operated type in which'any one of a series of keys 130 may be depressed and rocked about its pivot 10% to cause an operation of the machine. As the rear end of the key lever rises it will engage the key coupler 222, which extends across the rear ends of all of the key levers, and rocks the coupler about its pivot. Attached to one end of thecoupler is a rack element 650, having two sets of opposed rack teeth which are alternately adapted to engage and reoperation of a key lever, in which the pressure of the finger serves to produce the motive power for half of the rotation, while the weight of the key coupler serves to restore the parts and complete the rotation. All of this mechanism has been fully disclosed in the Fuller application, previously men tioned, and in many patents including patent to Carney 497,860, dated May 23, 1893.

Among the several functions of the shaft 106 is thatof causing the operation of an impression platen for taking an imprint from certain type carriers, and also of supplying the power for causing the automatic step by step movement of the inking ribbon, all as hereinafter explained.

Setting of type carriers by key levers.

It will be understood, of course, that a plurality of keys may be depressed during a single operation of the machine, in which case the several key levers will all engage and be latched to the key coupler 222, by means of the li 224 on the coupler entering the slots 225, 1n the keys. The action of only a single-key lever need be discussed herein, with relation to its effect on the differential mechanism for positioning the appropriate type.

As shown in Fig. 1, each key lever is provided with an upwardly extending arm 131, carrying a pin at its upper endwhich is surrounded by an anti-friction roller 131.

This roller is'adapted to cooperate with one or the other of the two branches of a cam slot 151, appearingin the cam plate 150. It will be understood that a cam plate is provided for each ofthe amount keys of the machine, and that each plate is adapted to receive and be acted upon by its corresponding roller 131'. A seri s of 9 such cam lates are united to form 'a single rigid memer, together with a rack segment 157, all loosely mounted on'a shaft 105 and the machine as a whole may comprise several such rigid units. v

The forward branch of the cam roove 151 of the several cam plates 150 wil vary according to the denomination of the key to which it corresponds,-so that as a one key is depressed its roller 131 will move the rigid cam element and hence the rack 157 merely a units distance, while a 9-key, for example,

will move its cam plate and hence the rack 157 a distance of 9 units. For the purpose of permitting the counter-clockwise rotation of the several cam plates by the action of one of them without interference with the remaining rollers 131, on the inactive keys, the rear branch of the cam slot 151 is designed to be concentric with the shaft 105.

As shown in Figure 1, the upper portion of the rack segment 157 engages a pinion 37 6 loosely mounted on a shaft 375, and rigidly connected to a type wheel 377. It will be apparent, therefore, that as the rack is moved differentially in accordance with the action of one of the series of keys on its corresponding cam plate 1501 the type wheel 377 will likewise be differentially rotated to present a corresponding type at the printing position.

Printer frame.

For the purpose of-supporting the various elements of the recording mechanism, other than the type wheels, as a single removable unit of the machine, a printer frame is employed which comprises a pair of side plates 400, connected by suitable cross rods and by the mainprinter operating shaft included in this mechanism. This frame which is best shown in Figs. 2 and 3 is supported by a forked projection extending from each of the plates 400 and surrounding the shaft 105. It is elsewhere supported by other portions of the frame contacting with fixed portions of the machine as a whole but as this feature is clearly disclosed in the Fuller application,

above referred to, it need not be particularly described herein;

Among the several features included in the printer unit is the record strip which, as best shown in Figure 1, extends from a supply roll 418 around suitable guide rolls, around the platen 410, around other guide Z-rolls and finally back to a take-up roller 417. The" details: of the manner of support ing the record strip as well as'the means for advancing it during the operation of the machine, are fully set forth in the Fuller lit) It will be noted from Fig. 2

that the cam race is open at the top to pery.

mit the insertion and removal of the roller whenever the shaft 106 is in its normal idle position. A spring 434 connecting a pin 436 on the arm 431 with a pin 435 on one of the frame plates 400, normally tends to hold the double arm in the position shown in Fig, 2, in which the arm 432 abuts a pin 419.

inking ribbon feeding and mechanism.

Another feature of the machine which is wholly supported by the printer frame above mentioned is the inking ribbon and: the mechanism for feeding it in either direction on successive operations of the machine.

Referring to Fig. 4, it will be seen that the ribbon is connected at each end to a suitable spool so that during the operation of the machine it may be fed from one spool-for example, that designated 20, over a suitable guide 11, between the impression platen and. the several type wheels shown in Fig. 1, over a second guide roller. 12 onto the opposite spool 22. The spool is loosely mounted on a spindle 24 which in turn is suitably supported as by a bracket 15 (best shown in Fig. 2) which bracket is connected to the left hand frame plate 400 by suitable fastening means, such as a pair of screws. Correspondingly, the spool 22 is loosely mounted on a spindle rotatably supported bya bracket 16 connected, as best shown'in Figure 3, to the right hand frame plate 400. The spools'20'and 22 are held on their spindles by suitable holding means, such as the pix'oted holding fingers 24 and 25.

For the purpose of rotating the spool 22 it is frictionally connected to a driving friction disk 49 secured to the spindle 25 and having teeth 49'. These teeth are engaged successively by a pawl 48 mounted at the end of one arm 46 of a bell crank pivoted at 47, and having its other arm engaged, by a pin and slot connection at 44, with an arm 43 secured to the previously mentioned shaft 430. t

It will be readily understood that as the shaft 430 is oscillated by the cam 429 on shaft 106, the pawl 48 will engage and draw downwardly, one of the teeth 49', thereby rotating the friction disk 49, andtending to rotate the spool 22. A spring 48 connected at one end to the pawl 48 and at the other end to arm 45 serves to hold the pawl in reversing engagement with the teeth 49.

Through this mechanism it will be seen that the spool 22 has a tendency to rotate always in the same direction on each operation of the machine, but as will be more apparent from the description which follows, this spool is at times rotated in the reverse direction by means opposing the normal friction drive. In Fig. 4 may be seen a dctvnt 13 which is urged by a spring 14 into the teeth of the driving friction disk 49 to prevent backward movement as the operating pawl 48 is raised.

that the pin 52 may Returning to the left hand spool, it may be seen from Figs. 5 5, 5, 5 and 5, that a pinion 50 is loosely mounted on the spindle 24 and carries a pin 19 which is adapted to cooperate with a slot 191 (Fig. 4) in the side'of the spool 20, so that the two elements fiazy rotate together when properly assem- For the purpose of rotating the pinion 50 and hence the spool 20, there is provided a double pawl 51 having two actuating teeth or projections 511 and 512, which are alternately adapted to engage and rotate the pinion in accordance with the direction of rotation to be given to the spool. The pawl 51 carries a pin 52 which is adapted to cooperate with a slot 531 (best shown in Fig. 6) formed in a rocking plate 53. In order be yielding-1y retained in either one end or the other of the slot 531, a slight hump 532 is provided at the central portion'of said slot so that there is a. tendency for the pin 52 to remain between this hump and one or the other end of the slot, depending upon which of the pawl projections is effective.

As a further means for yieldingly holding the pin 52 in the desired end of the slot, I

a spring pressed arm 04, acted on by a spring 56, is designed to press against the pawl 51 at or near one of the two ends of .a notch 513 formed therein, said notch being so designed that its ends are at opposite sides of pivot 52. The spring pressed arm 54 serves, therefore, the additional function of rotating the pawl 51 about its pin" 52 as a center, to engage the appropriate projection 511 or 512. Thus if the pin 52 is in the lower end of the slot 531, as shown in Figure 5 the nose 55 of arm 54 willengage the pawl at the upper end of the notch 513, thus tending to rotate the pawl in a clockwise direction. On the other hand, if the pin52 is lodged in the upper end of the slot 531, as shown in Figure 5 the nose of arm 54 will engage in the lower end of notch 513 and tend to produce a counterclockwise rotation of the pawl 51 to render the projection 511 effective.

By reference to Figure 6, it will be noted that the plate 53 is connected by a pin 488 to the upper end of a link 489, which as shown in Fig. 2, has its lower end connected to one arm of the lever 490. This lever in turn has its other arm forked to produce a cam slot which will engage a pin 491 on the previously mentioned arm 432 so that on each operation of the machine this entire train of mechanism will be reciprocated with the result of rocking the plate 53 about the spindle 24 through a definite arc to cause a complete pawl 51.

If no means were provided to prevent a return movement of the pinion 50 it is obreciprocation of the actuating quently will permit an undesirable rotation of the parts in a direction reverse to that in which the parts are intended to be rotated and they strongly resist rotation-of the ribbon spool in the desired direction. By the present. invention these difliculties have been overcome through the employment of a pair of detents 58 and 59, preferably mounted in scissors fashion upon a single supporting pin 60. Each detent is designed to prevent rotation of the pinion in only one direction and to permit of a very easy operation of the pinion in the other direction. lVhile' both of the detents are normally urged toward active position by a spring 61 interposed between their opposite ends 62, means are provided for preventing the action of oneof the detents while the other remains effective. This controlling means is pref erably in the form of a plate 63 which is loosely mounted-on the spindle 24 for adjustment to either of two positions and carries a pair of pins 64 and 65 which are adapted, to cooperate respectively with suitable notches in the detents 58 and 59.

As best illustrated in'Figs. 5 to 5 the detent 58 is provided with two notches 641 and 642, adapted to receive the pin 64 at different times. Similarly the detent 59 is provided with notches 651 and 652 to receive the pin 65 at difi'erent times. When the pin 64 is in the notch 641 and pin 65 is in the notch 652 (as shown in Fig. 5 the detent 59 is eflective to prevent clockwise rotation of the pinion 50, while the detent 58 is maintained inan inactive position. On the other hand, should thepins 64 and 65 be moved to engage the notches 642 and 651, respectively, the detent 58 would be effective to prevent counter-clockwise movement of the pinion 50 while the detent 59 would be held in its inactive position as shown in Fig. 5

It will be obvious that the action of the detents must be coordinated with the action of the driving pawl 51 so that as the pinion 50 is being rotated by the pawl 51 in a counter-clockwise direction, by means of the projection 512, the detent 59 will pre- I vent clockwise movement of the pinion, and

as the pinion is being rotated clockwise by profection 51 1 detent 58 will prevent coun- I tar-clockwise rotation.

To accomplish the coordination between the activity of the driving pawl 51 and the two detents the detent controlling plate 63 is provided with two laterally extending hook portions 66 and 67 which are adapted to cooperate, respectively, with pins 68 and 69 carried by the operating pawl. The relation between the two hooks and the pair of pins is such that only one of the hooks will be in the path of movement of its corresponding pin during any operation of the ma chine, the other hook being at this time out of the range of movementof its pin. Thus. as shown in Fig. 5 the hook 67 is in direct line with the pin 69 carried by the upper branch of the actuating pawl so that the controlling plate 63 willbc rocked clockwise to render the detent 59 active and detent- 58 inactive. At the same time, pin 68, as shown, will be beyond the hook 66 so that during the reciprocation of the double pawl there will be no engagement between these elements. On the other hand, when the double pawl is'moved to its upper position with respect to slot 531 the pin 68 is moved into the path of hook 66 while pin 69 is 'plate.

In this connection it may be noted that the pair of detents 58 and 59 serve the additional function of yieldingly retaining the controlling plate in either of its two positions of adjustment, it being necessary in moving the plate to force both of the detents apart in scissors fashion against the force of the spring 61.

For the purpose of forcing the inking ribbon as well as the record strip against the type wheels 37 7 to form a printed entry the impression platen 410 about which the record strip passes, in its travel from the supply roll to the storage roll, is given a quick downward movement by mechanism operated from the previously mentioned shaft 430. This mechanism, as fully disclosed in the continued movement of the arm 437 the shoulder 438 will move beyond the upper end of arm 4150 and will permit the spring 44.7 to drive the hammer upwardly and thereby strike a projection on a lever 411 which is secured as a rearward extension of the swinging platen. It will be clear that a sharp downward movement of the platen mentof shaft 106 the left hand spool.

410 about its pivot 406 will result.

The purpose of mounting the lever 450 pivotally on the hammer 445 is to permit the lever to rock backwardly without affecting the position of the hammer as the arm 437 is restored to its normal position.

Operation.

The operation of the machine will now be briefly described with particular emphasis on the movements of the ribbon reversing elements.

As a key 130 is rocked the upwardly extending arm 131 will cause its roller 131 to engage the, wall of the cam slot 151 and thereby rock the differential element. comprised by plates 150 and rack element 157, about the shaft 105. This movement will be transmitted by pinion 376 to the type wheel 377. At the same time the rearward end of the key lever will engage and rock the key coupler 222 to lift the rack 650 and cause a half rotation of the shaft 106, after which the weight of the key coupler will restore the parts to complete the rotation of shaft 106.

Among the several functions of this main operating shaft of the machine are those of shifting the record strip from the supply to the storage roll and causing the impression movement of the platen 410, but the operation of these parts need not be summarized.

A further function of the main operating shaft is to cause the feed of the inking ribbon 10 from one spool to the other and back again, with provisions for automatically causing a reversal of this movement. As best shown in Figures 2 and 3, the moveis first transmitted by bell crank 431-432 to the shaft 430; this movement is then transmitted by arm 43, bell crank -46, and pawl 48, to a friction disk 49 mountedon spindle 25. The friction disk. is rotated on each operation of the machine a Single space between the teeth 49 in a clockwise direction. as shown in Fig. 4, and it tends at all times to rotate the right hand spool 22 in the same direction. Other connections comprised by a pin 491 on the arm 432, lever 490. and link 489. serve to transmit motion from the shaft 430 to a roclt'ing'plate 53, which constitutes the operating source for the driving mechanism of The pawl 51 mounted by a pin 52 in a slot 531 of the controlling plate 63 serves to rotate the pinion 50, and hence the s 001 20, in either direction, according to w ich of the projections 511 and 512 is effective. The active end of the pawl is held in engagement with the pinion by means of the spring pressed arm 54. Backward rotation of the pinion i. e.', in a direction opposed to that in which it is being driven at a given time, is prevented by either of the pair of detents 58 and 59. These detents are under the control of the controlling plate 63, which has two positions of adjustment, one as shown in Fig. 5 in which the pins 64 and 65 hold the detent 59. effective, and detent 58 ineffective, and the other as shown in Fig. 5 in which these pins reverse the action of the detents. The controlling plate in turn is shifted by the pawl 51 through pins 68 and 69 to co-ordinate the two ends of the pawl with the two detents, so that either the projection 511 and detent 58, or theprojection 512 and detent 59, will be effective.

, When the parts are in their normal position, as shown in Fig. 5 and the pinion 50 is being rotated in a counter-clockwise direction, the pin (39 will rest in the cavity of the hook 67, since it has on some previous operation engaged the hook toward theend of the return stroke and shifted the controlling plate 63 to its position'there shown. As the rocking plate 53 is drawn downwardly the pawl projection 512 will turn the pinion 50 one tooth space until the detent 59 drops behind the next succeeding tooth. While the rocking plate is being restored to its normal position the pawl 51 will be slightly rotated by the engagement of the projection 512 with the teeth of the pinion 50, as shown in Fig. 5 but no reverse rotation will be given to the pinion due to the action of the de tent 59.

During the successive operations of the machine the ribbon 10 will gradually be wound upon the spool 20 until the supply from spool 22 is completely exhausted. At this time a further attempt to rotate spool 20 will be resisted by the tension of the ribbon so that as the rocking plate 53 is moved downwardly it cannot carry the pawl 51 with it. This will result in a relative movement between the plate andthe pawl so that the pin '52 will now assume a position at the upper end of slot 531, as shown in Fig. 5. The spring pressed arm 54 will then reverse its action on the pawl 51 and tend to rock the projection 511 intofactive position. This action, however, will be prevented by the engagement of pin 68 with the periphery of the hook 66, until the upward movement of the plate 53 has been suflicient to remove the pin from the hook. At the end of this operation of the machine the parts will assume the positions shown in Fig. 5 in which the pawl project-ion 511 and the detent 59 are in effective positions. However, on the next operation of the machine the pin 68 will be in a position to engage the hook 66 and thereby rock the late 63 to reverse the activity of the two etents. The pawl projection 511 may now grip one-of the teeth of the pinion 50 and rotate it a single tooth space as the plate 53 is rocked back to its normal position. Fig. discloses the parts in the positions they will assume after the return movementof the rocking plate 53 has begun. Successive operations of the machine will now serve to rotate the pinion 50 and hence the spool in a clockwise direction, while at the same time the spool 22 is being frictionally driven to take up the slack in the ribbon that is thus produced. When the supply has been completely exhausted from the spool 20 it will continue in its clockwise rotation and will serve to rewind the ribbon by the action of the'same pawl projection 511. It is not until the ribbon has been completely unwound from the spool 22 again that another reversal of the parts will take place to render the pawl projection 512 and detent 59 effective. This reversal will take place in substantially the same way as that above described in detail. 6

It may be noted that as shown the distance between the two hooks 66 and 67 is slightly greater than that between the pins 68 and 69. Should the ribbon be exhausted from spool 22 at the outset of an operation, from the position shown in Fig. 5 the pawl 51 would be held stationary until the plate 53 had moved to engage the upper end of the slot 531 with the pin 52, at which time the lever 54 would rock the pawl about its piv- 0t 52 so that during the remainder of the same operation of the machine the shifting of the detent controlling plate 63 could be effected by pin 68.

It should be stated that the movement of the plate 53 is suflicient to account for both the movement of the pin 52 in the slot 531 and the rocking movement of the controlling plate 63. However, since in most operations of the machine the ribbon 10' will not become sufficiently taut to hold the pawl 51 firmly, until the operation has been partially carried out, it will usually require a second operation of the machine, and in some constructions possibly a third, to cause a shifting of the detents as in the operation first described.

While the preferred embodiment has been illustrated and described it is not intended to limit the invention to the precise form disclosed as it is obvious that changes may be made within the scope of the claims which follow.

What is claimed is 1. In a machine of the class described ribbon mechanism comprising a pair of rotatable spools adapted to be rotated in either direction, friction means tending to turn one ceive opposite ends of an inking ribbon, 7

means for rotating one of said spools in only one direction, means for rotating the second of said spools in either direction, said last mentioned means being adapted to reverse its direction of rotation as the ribbon is $9 exhausted from the opposite s 001, and detent means under control of sai second spool rotating means for preventmg rotatlon 1n the non-actlve dlrection.

3. In a device of the class described, a pinion mounted on a spindle, a plate-mounted for oscillation on said spindle, a double pawl member adjustably carried by said plate and adapted to engage said pinion to rotate it in either direction depending 11 tion of adjustment of said doub e pawl, a detent controlling element mounted on said spindle and in turn controlled by said double pawl, a pair of detents adjacent said pinion to prevent reverse rotations, and means car- 95 ried by said controlling element to govern the action of said detents.

4. In a device of the class described, a pinion mounted on a spindle, means for rotating said pinion in either direction, means for reversing the direction of action of said rotating means, a pair of detents effective singly to prevent rotation of said inion in a direction opposite to the action 0 said rotatin means, and means operated by said 1 rotatmg means to change the etfectivity of said detents as the direction of action of said rotating means is reversed.

5. Inamachine of the class described. an inking ribbon, a pair of spools adapted to I receive opposite ends of said ribbon, means for driving one of said spools in one direction only, means for driving the other of said spools in either direction, and'a pair of detents adapted at all times to prevent rotation of said last mentioned spool in a direction opposite to that in which it is being driven.

6. Ribbon mechanism comprisin a spool spindle, a spool loosely mounted thereon, a pinion mounted on said spindle and adapted to rotate said spool, a rocking plate' pivoted about said spindle and adapted to receive an oscillating movement, a double pawl having a pair of projections and adl ustably mounted for movement with said plate, said pawl being bodily adjustable on said plate. means engaging said pawl to hold either projection alternatively in engagement Wl'th said pinion whereby the latter may be l n the posidouble pawl bodily adjustable on said rocking plate and provided with integral projections for engaging said pinion at opposite sides, means for holding either of said'procctions in active engagement with said pinion while the other is inactive whereby as the plate is rocked the active projection will pull the pinion with it, and means for preventing" rotation of the pinion as the projection is pushed acrossits teeth.

8. Ribbon mechanism comprising a spool having a pinion connected thereto and mounted for rotation in either direction, a rocking plate adapted to be oscillated, a double pawl bodily adjustable on said rocking plate and provided with integral projec tions for engaging said pinion at opposite sides, means for holding either of said projections in active engagement with said pinion while the other is inactive whereby as the plate is rocked the active projection will rotate the pinion in one direction, and means for preventing rotation of the pinion as the projection is moved in the reverse direction.

9. Ribbon mechanism comprising a spool mounted on a spindle, a pinion mounted on said spindle and adapted to rotate said spool in either-direction, a double pawl adapted to be oscillated to rotate said pinion in either direction, a pair of detentseach adapted to.

prevent one direction of rotation of said pinion, an adjustable controlling plate to selectively render one of said detents efiective, and interengaging elements carried by said double pawl and said controlling plate whereby the pawl may shift the controlling plate to coordinate said detents with the dircction of rotation imparted to said pinion.

10. In a machine of the class described, difl'erentiallv settable type elements, means for setting the same, record strip supporting and feeding means, a pair of spools adapted to support the opposite ends of an inking ribbon which is passed intermediate its ends between a record strip and said type elements, means for moving the ribbon in either direction, said means being capable of automatically reversing its direction oi activity by an excess tension in the ribbon and being controlled solely at one of the spools, and two separate means for preventing one or theother direction of rotation of said last mentioned spool at different times.

11. In a machine of the class described, manually depressible keys, type elements differentially set by depression of said keys, means operated by said keys for shifting a record strip relative to said type elements, impression means operated by said keys, a pair of spools adapted to support an inking ribbon at its ends, said ribbon being adapted to pass between said type elements and said impression means, means operated by said keys to directly drive one of said spools in either direction and adapted to reverse the direction of rotation when the tension in the ribbon is increased, and means for positiv'ely preventing rotation of saidv spool in a direction opposite to that in which it is intended to be driven.

' 12. In a machine of the class described, a pair of spools mounted for rotation, an inking ribbon having an end fastened to each spool and adapted to be wound alternately on each spool, means for rotating one of said spools to first unwind the ribbon therefrom and then to rewind it thereon by a constant direction of rotation, means for automatically reversing the direction of rotation of said spool when the ribbon is completely rewound and means for positive- 1y preventing rotation of said spool in a direction opposite to the action of said rotating means.

13. Ribbon feeding mechanism comprising apair of ribbon spools-each adapted to receive one end of a ribbon, means for positively driving one of said spools in either direction, means for automatically reversing the direction of activity of said driving means and a pair of co-operating detents to positively prevent rotation of said spool in the non-active direction at all times.

7 14. In an automatically reversible ribbon driving, mechanism, a supporting bracket, a spool spindle secured therein, a plnion mounted on said spindle, a spool having operative connection with said pinion, an operating member provided with means for rotating said pinion in either direction, said member being mounted for movement about said spindle, and a pair of detentspivotally mounted on said support, and adapted to alternatively prevent rotation of said pinion in one direction or the other.

15. In an automatically reversible ribbon driving mechanism, a supporting bracket, a spool spindle secured therein, a pinion mounted on said spindle, a spool having operative connection with said pinion, an operating member provided with means for rotating said pinion in either direction, said member being mounted for movement about said spindle, and a pair of detents mounted on a single stud carried by said support and adapted to prevent rotation of said pinion opposite to thatintended to be imparted by said operating member.

16. In a reversible ribbon driving mechanism, a spindle, a pinion rotatably mounttoo ed thereon; a ribbon spool connected with said pinion for rotation therewith, an adjustable actuating pawl adapted to rotate said pinion in either direction accordin to the position of adjustment of the paw a pair of detents adapted to prevent rotation of the pinion in a direction opposite to the driving action of said pawl, and a controlling plate governing the action of said detents, said plate being under the control of W said pawl.

In Witness whereof I have signed my name hereto this 22 day of January 1924.

WALTER E. LIPPERT. 

